Railway track circuits



Oct. 27, 1931. H, BONE 1,828,994

RAILWAY TRACK CIRCUITS Filed April 14, 1931 INVENTOR;

Y e R. PM

- ATTORNEY.

Patented Oct. 2 7, 1931 UNITED STATES SPA-TENT? OFFICE HERBERT BONE, OF SWISSVALE, PENNSYLVANIA, ASSIGNOB' T THEUNION SWITCH; & SIGNAL COMPANY, O'FSWISSVALE, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

Application filed April 14,

My invention relates to railway track circuits, and particularly to track circuits which are used for locking a switch and thereby preventing the switch from being moved 6' while a car is passing through the switch.

The present invention is especially suitable for use in connection with the switches in freight classification yards. The minimum spacing between cars which are being classified in such yards is determined by the length of the switch detector track circuit, and the greater the spacing between cars, the slower is the operation of the yard. It is desirable, therefore, to keep the detector track circuits as short as possible.

The conventional freigth car has a wheel base of 37 feet or less, and the spacing between the inner wheels of the two trucks is about 27 feet. It follows that for conventional freight cars, a track circuit 27 ft. long will prevent the switch from being thrown betweenthe trucks of a car. Special steel cars are being built at'the present time, however, for the handling of structural steel, and the spacing between the inner wheels of the two trucks of these cars is approximately 54 ft. It follows that for these special cars a track circuit 54 ft. long is required in order to prevent the switch being thrown between the trucks.

One feature of my'invention is the provision of a track circuit which will operate to a release the switch as soon as the rear wheels of the conventional freight car have passed the switch, but which will function to prevent the switch being thrown between the trucks of the special steel cars hereinbefore referred to. i

I will describe one form of track circuit embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic View showing one form of track circuit embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a railway track, which rails are connected with the rails 10 and 10 of a branch track by a switch S. g The rail 1 is divided by in sulated joints 2 to form an insulated section RAILWAY TRACK, crncnrrs 1931. Serial No. 530,020.

AB, the point A beinglocated immediatelyin'advance of the switch S. The rail 1 is divided by similar joints to form a section CD. The two sections A-B and C-D are staggered, but overlap. length of each section may be 54: ft., and the length of the overlapping portions between the points A and D may be 27 ft. A source of track circuit current 3 is connected from the right-hand end of section AB to the right-hand end of section CD, a current limiting resistance 4 being interposed betweenthese rails and the rail 1. A track relay5 is connected from the left-hand end of section Al3 to the left-hand end of section 0T5 CD. It is understood that the relay 5 controls the switch S in the usual and well known manner, so that the switch cannot be moved unless the relay is energized.

Preferably, the rail 1 is provided with an" auxiliary section DF, the point F being located opposite the point B, and the rail 1 is provided with a similar auxiliary section EA, the point E being located opposite the point C. The only purpose of these if the insulated joints 2 were not provided at points E and F. V

The rails 10 and 10 of the branch track are tied into the track circuit for the rails 1 and 1 in the usual manner.

Assuming that aconventional freightcar moving toward the left, passes through the track circuit, 1t Wlll be seen that thislcar has no effect on the track relay until the firstpair of wheels passes the point D. The relay will then be shunted and will remain shunted until the last pair of wheels passes the point A. Relay 5 will then immediately become energized. That is to say, the spacing between the inner wheels of the two trucks of the car is less than the distance between points A and D, so that while the car is passing through the track circuit, it can not bridge the portion of track between these two points. I

When a special steel car passesthrough For example, the

the track circuit, it will, likewise, have no efi'ect until the first wheels pass the point D, whereupon, the relay 5 will be shunted. After the forward truck passes the point A, '5' there will be an interval of time during which there are no Wheels of the car between points A and D, but during this time one truck will be between points E and A, and the other truck will be between points D and F. During this time relay 5 will still be shunted, because there will be a complete path of low resistance from the left-hand terminal of the relay through the rail 1, the forward truck, the steel body of the car, the rear truck of the car, and the rail 1, to the right-hand terminal of relay 5. The resistance of this path will be sufiiciently low to keep the relay 5 deenergized. As soon as the rec" wheels of the car pass the point A, relay 1 again become energized to release the switch S.

It follows that by means of a track circuit embodying m invention, it is impossible to throw the switch S under either the conventi-onal freight car or the special steel freight car, and yet the track circuit places no limitation on the spacing of the cars passing through the classification yard.

Although I have herein shown and descrioed only one form of track circuit, em-

co my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A railway switch detector track circuit comprising staggered insulated sections in the two track rails overlapping by an amount greater than the distance between the inner wheels of the two trucks of a standard freight car but less than the distance between the inner wheels oi the two, trucks of a special steel freight car, a source of current connected across said sections at one end, and a track relay connected across said sections at the other end.

2. A railway switch detector track circuit comprising staggered but overlapping main use sections in the two track rails, an y insulated section in each rail exng from the associated main section to I A nt opposite the end of the main section in the other rail, a source of current connected across said main sections at one end, and a track relay connected across said main sections at the other end.

In testimony whereof I aflix my signature.

so HERBERT L. BONE. 

